Control apparatus



Oct. 23, 1934.

G. H. RocKwoOD 1,977,697 l CONTROL APPARATUS Filed oct. 23, 1929Patented ct.- 23,` 1934 UNITED STATES PATENT OFFICE 1,911,691 comm.APPARATUS GeorgeRBoekwoolmParLllLassig-norto Western Blech-ie Company,Incorporated, New York, N. Y., a corporation of New York ApplicationOctober 23,

SGaim.

5 of a simple and eilicient measuring or controlling apparatus.

In accordance with one embodiment, the invention contemplates theprovision of 'apparatus for winding resistance wire about a mandrel toform I l a resistance coil and simultaneously measuring the resistanceof the coil by connecting it in an arm of a Wheatstone bridge circuit.When a predetermined amount of wire has been wound on the coil, thebridge circuit will be unbalanced l in -a direction opposite to itsunbalanee when less than the predetermined amount is wound ther-con andcurrent will flow from the bridge through a transformer to increase thevoltage before directingitfothegridofavacuumtube. The

Nvacuum-tubeisof atypewhereinifthegrid voltage thereof is more negativethan the plate voltage divided by the amplification factor oit the tubeno plate current will iiow and if the grid voltage is less negative thanthis value the plate current is determined bytheplatevoltsgeand theresistance in the plate circuit.

The plate circuit of the vacuum tube is connected to a. control relaywhich is effective to complete a circuit to an electromagneticallyoperated knife and an electromagnetically operated brake. Upon thereversal of the direction of iiow of current across the bridge circuitthe grid voltage will immediately become less negative than the platevoltage divided by the ampliiication '35 factor ofthe tube therebycausing an ampliiled flow of current in the platecixcint of the tube andthe consequent operation of the control relay, which will completecircuits to operate the knife and the brake, severing the strand whichis passing under the knife and interrupting the rotation of the spoolfrom which the strand of wire is being drawn.

A clear understanding of the invention will -be had by reference to thefollowing detailed description taken in conjunction with the aeeom'panying drawing, wherein a single schematic view shows diagrammaticallythe featmes thereoi' and wherein like reference numerals designate thesame parts.

The numeral 1 designates a supply spool from which a strand 2 ofresistance wire is drawn overgmdes3and4toarotatingfiattypecoil base 5.Thebaseispositlonedbetweenachuek B'rotated by a motor 10 and a freelyrotatable chuck 11. Theforwauiendofthewixemaybe 1929, Serial No. 401,947

attached to the chuck 6 by means' of a clip 12 provided therefor. y

A knife 13 cooperates with the guide 3 to form a shearing mechanismwhich is designed to be actuated by .an electromagnet 14, the armature15 of which engages a slot 16 in the knife. The

armature is normally retained in the position shown by means of a spring20 which tends to rotate it about a pivot 21 provided therefor. When thelcuife 13 is actuated to sever the wire, the spool 1 wouldnomially-continue to rotate due to its momentum so there is provided abrak-- ing mechanism therefor designated generally by the numeral 22 andcomprising an electromagnet 23 having an armature 24 pivoted at 25 andcarrying on an-arm thereof a braking member 26 which, upon energizationof the electromagnet 23, will engage the periphery of the spool and itsrotation. I

The motor l0 is connected to a source of electxonwtive force by means ofa dou-ble pole switch 30 which when closed completes a circuit from a.line conductor 31 through conductors 32, 33, and. 34 "to the motor andfrom the motor through condoctors 35, 36, and 37 back .to the other sideof the line at 38. In the particular embodiment of the inventiondisclosed herein, the conductors 31 and 38 are supplied with directcurrent at 110 volts.

when closed, the switch 30 also completes a circuit from the lineconductor 31 through the conductor 32 and a conductor 40 to the windingof a. relay 41 and through the winding of the relay, a conductor 42, andthe conductor 37 back to the line at 38. lThe relay 4l will thus beenergized simultaneously with the starting of the motor 10 and willattract its armature 43 to complete circuits t0 be described in detailhereillafter. A relay 44 is also' connected to the conductors 33 and 36and will be energized when the switch 30 is closed. This relay is madeto respend slowly to the current supplied thereto by connectingan'impedance coil 45 in a lead 46 connecting one side ofthe winding ofthe relay to the conductor 33 and by connecting a resistance coil 50between the lead 46, at a point intermediate the impedance coil 45 andthe relay 44, and a lead 51 which connects the other side of the windingof the relay 44 to the conductor 36. The relay 44, upon being energized,acts slowly to attract an armature 52 associated therewith and close twocontacts 53 and 54 to connect a. conductor 55 to a pair of conductors 56and 57, respectively. The. conductor 55, in the particular embodimentdisclosed herein, is connected lic to a source of direct current at 48volts. A pair of xed condensers and 61 are connected be tween the leads56 and 57, respectively, and the line conductor/55.

When the switch 30 is closed manually the motor l0 will be started, therelay 41 will be energged, and immediately thereafter the relay 44 willclose the contacts 53 and 54. The energization of the relay 41 willclose a contact at 62 to connect a lead 63 running to one end of thesecondary winding of a three winding transformer 64, the other end ofwhich is connected to ground at 65, to a lead- 66l connected to aWheatstone bridge circuit designated generally by the numeral 67. Theenergization of the relay 44 will connect the line conductor 55 throughtheconductors 56 and 57`to movable contacts 70 and 71, respectively, ofa relay 72 which, upon being energized in a manner to bedescribed morein detail hereinafter, will move the contacts 70 and 71 into engagementwith a pair of stationary contacts-73 and 74, respectively. Connected tothe stationary contacts 73 and 74 are a pair of conductors 75 and 76which are connected to one end of the windings of the electromagnets 23and 14, respectively. Shunts 77 and 78 connect the conductors 56 and 57to the conductors and 76 through condensers 79 and 80, respectively. Theother terminals of the windings of the electromagnets 23 and 14 areconnected through conductors 81 and 82 to the other side of the 48 voltdirect current line; Thus, the energization of the relay 72 will causethe actuation ofthe electromagnets 1'4 and 23, which will thereuponsever the wire and sto the rotation of the spool 1.

The transformer 64, which supplies electrical energy to the Wheatstonebridge circuit, has its primary winding connected by conductors 83 and84 to the output of a voltage regulator 85 which is connected to lineconductors 86 and 87 which supply 110-volt, 60-cycle alternating currentthereto. This transformer also supplies` current to a filament of avacuum tube 91 through conductors 92 and 93-connected to a secondarywinding thereof, a lead 94 from which is connected to the movablecontact of'a potentiometer 95.

The potentiometer 95 is connected to the line conductors- 86 and 87 byconductors 96 and 97, respectively, which are in -turn connected to oneend of the secondary winding of a transformer having a high impedanceratio and through a resistance 101 to the relay. 72 by conductors 102and 103, respectively. The other end ofthe winding of the secondary ofthe transformer 100 is connected to a grid 104 of the vacuum tube 91through condenser 105 which is shunted by a resistance 106. The otherend of the..winding of the relay 72 is connected by a conductor 107 to aplate 110 of a vacuum tube 91 and the conducbridge, and across the.bridge to a point 113 thereof which is connected to ground at 114.

l Arms 115 and 11s of the Wheatstone bridge s1 are of equal resistance,and arm 117 is of known ristance and may be varied while the wirebetween the guide 3 and the clip 12 forms the fourth arm of theWheatstone bridge. To include the wire between these points in this armof the bridge a brush 120 contacts with the chuck 6 andv is connected toground at 121 by a conductor 122 and the guide 3 is connected to a point123 of the Wheatstone bridge by conductors 124 and 125. The point 126 onthe bridge opposite the point 123 is connected to one end of the primarywinding of the transformer 100 by a conductor 127 and the other end ofthe primary winding of the transformer 100A is connected to the point123 by the4 conductor 125.

The apparatus and circuit for controlling the mechanism having beendescribed in detail, a clear understanding will be had by referring to-the following description of the operation thereof: The resistance ofarm 117 is adjusted to that desired in the finished resistance coil, anda strand of wire 2 is drawn from the spool 1- and connected to the clip12 on the chuck 6, passing over age to the Wheatstone bridge circuit 67.Shortly f after the relay 41 operates the relay 44, which is alsocontrolled by the closing of the switch 30, will be energized and willattract its armature 52 to close the contacts 53 and 54. The closing ofthe switch 30 and the consequent actuation of the relay 41 applies thevoltage tothe bridge circuit and may cause a switching transient currentin the circuit as a whole, which will cause the relay 72 to be operatedmomentarily. However, since the slow acting relay 44 does not closeuntil an appreciable time after the relay 41 has attracted its armature,such a transient current will be dissipated before the circuits are com-1 pleted to supply power to the electromagnets 14 and 23. Uponenerglzation of the relay 44 power will be placed upon the open contacts70 and 71 so that when the relay 72 is subsequently energized.l thebrake 22 and the knife 13 will be 120 that of the arm 117. However, whenthe desired amount of lresistance is reached inthe coil being wound theflow of plate current in the tube is established to cause the relay 72to operate, whereupon the brake and knife will be actuated. While in thespecic embodiment of the invention disclosed herein the coils beingwound are formed of uninsulated wire, it is to be understood that coilsof insulated wire might also be formed by simply adapting the apparatusdescribed above so that a coil having a length of wire greater thannecessary to form the resistance required could be wound and thereafterunwound and simulta- .neously scraped of insulation while in contactwith a guide member 'similar to the Aguide member 3, appropriate changesin the circuit connections being made so that the plate current of thetube would beging to flow as soon as the resistance of the coil beingmeasured became less than a predetermined amount rather than more than apredetermined amount as disclosed herein.

What is claimed is:`

1. In apparatus -for handling strand material, means for winding astrand, a Wheatstone bridgecircuit, Imeans for continuously includingthewound strand as the unknown arm of the Wheat- 1' stone bridgecircuit, a thermionic valve, means for establishing a f'low of currentin the plate of the valve under control of the potential in the grid ofthe valve and in response to a change in the direction of flow ofcurrent across the bridge, and means controlled by the thermionic valvefor severing the strand when the resistance of the Wound strandconstituting the unknown arm balances the bridge circuit.

2. In apparatus for winding resistance coils, means for advancing astrand and winding it into a coil, a xed contact member positionedadjacent the path of the strand during its advancement, a Wheatstonebridge circuit, means for including the portion of the strand positionedforwardly of the contacting member as an arm of the Wheatstone bridgecircuit, a thermionic valve responsive to a change in resistance of theportion of the strand positioned forwardly of the contact member andoperative upon a change in a direction of flow of the output voltage ofthe bridge, and means controlled by the thermionic valve for severingthe strand when the resistance of the advanced strand constituting theunknown 1' arm of the bridge circuit balances the bridge.

3. In a measuring apparatus, a winding arbo a terminal upon the windingarbor for receiving the forward end of a strand to be wound upon saidarbor,a cutting. knife, a bridge circuit having three arms of knownresistance, means for engaging the strand adjacent said cutting knife.means electrically connected to said strand engaging means and saidterminal for continuously including the strand therebetween as theunknown arm of the bridge circuit. and means actuated when the woundstrand balances the bridge circuit for actuating said cutting knife forcute ting the strand.

4. In a measuring apparatus, a supply spool of strand material, meansfor vrotatably supporting i said spool, a winding arbor for winding thestrand from the spool, a terminal disposed upon said winding arbor forreceiving the forward end of the strand, a cutting knife, a bridgecircuit having three arms of known resistance, means for engaging thestrand adjacent said cutting-knife, means electrically connected to saidengaging means and said terminal for continuously including the strandtherebetween as the unknown arm of the bridge circuit, means actuatedwhen the wound strand balances the bridge circuit for actuating thecutting knife for cutting the strand. a brake, and means for actuatingsaid brake for stopping the rotation of said mipply spool upon theactuation of said cutting knife.

5. In an apparatus for handling strand material, means for advancing astrand of material,

a nxed material engaging member positioned adjacent the path of thestrand during its advancement, a severing element positioned adjacentsaid mem means for measuring the resistance of the strand positionedforwardly of said member, and means controlled by said measuring meansfor actuating said severing element when the resistance of the measuredstrand has reached a predetermined value for severing the strand.

GEORGE H. ROCKWOOD.

Ill)v

